The digital platforms or gateways currently on the market propose multi-services via wireless links. They must therefore be able to support diverse standards such as the standards for digital telephone communications implementing the DECT (Digital Enhanced Cordless Telephone) function or the standards for high bitrate wireless communications such as the IEEE802.11a, b, g standards.
Moreover, this type of wireless communication is sometimes carried out inside a premise and, in this case, multiple paths phenomena are observed that are very penalising for the quality of the signal received, particularly the interference phenomena that provoke a fading of signals.
To overcome the above problems, antenna systems with a diversity order of 2 are used. However to obtain correct diversity, it is necessary that the two antennas are perfectly decorrelated. Hence, those skilled in the art have a tendency to space out the antennas from each other. However, the wireless communication devices, currently on the market, are more and more compact, which poses a problem with respect to the location of antennas realised directly on the electronic card receiving the other processing circuits.
Various solutions have been proposed to overcome the disadvantages mentioned above. Thus, in the patent application WO2007/006982 in the name of THOMSON Licensing, it has been proposed to integrate two F-inverted type antennas back to back on an electronic card. To improve the decoupling between the two F-inverted type antennas, a slot of length λg/4 is preferably provided. An antenna system of this type is shown in FIG. 1.